Debugging apparatus and method

ABSTRACT

A debugging apparatus and method are provided. The debugging apparatus may include a breakpoint setting unit configured to store a first instruction corresponding to a breakpoint in a table, stop a program currently being executed, and insert a breakpoint instruction including current location information of the first instruction into the breakpoint; and an instruction execution unit configured to selectively execute one of the breakpoint instruction and the first instruction according to a value of a status bit.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit under 35 U.S.C. §119(a) of KoreanPatent Application No. 10-2010-0098404, filed on Oct. 8, 2010, in theKorean Intellectual Property Office, the entire disclosure of which isincorporated herein by reference for all purposes.

BACKGROUND

1. Field

The following description relates to a debugging apparatus and methodfor stopping a program currently being executed and debugging theprogram.

2. Description of the Related Art

A breakpoint is an intentional stopping or pausing place in a program,put in place for debugging purposes. In order to debug a program, theprogram must be stopped even in the middle of being executed. Thesuspension of a program currently being executed may be performed bysetting a breakpoint in a particular part of the program code. Thesetting of a breakpoint may be performed using either a hardware-basedmethod or a software-based method.

The hardware-based method is characterized by providing a limited numberof registers in a system at the time of the design of the system andinserting an instruction address, which is the address of an instructionwhere the execution of a program is stopped, in the registers, so thatthe program can stop when then the registers and a program counter hitthe same value. As an example, the x86 instruction set architectureprovides hardware support for breakpoints with its x86 debug registers.However, since the number of registers installed in the system islimited, there is a limit in setting multiple breakpoints using thehardware-based method.

The software-based method is characterized by inserting, during theexecution of a program, an instruction that stops the program into theprogram to set a breakpoint. The program is stopped when encounteringthe instruction, and the system is switched to a debugging mode.However, when the system is switched back to a normal mode, a facebreakpoint may be set in the system, and thus, the performance of thesystem may deteriorate due to memory read/write operations. That is, inorder to resume the program, an operation originally at the address ofthe instruction needs to be restored, and the setting of the breakpointneeds to be maintained. Thus, a fake breakpoint is set in the nextinstruction. Thereafter, when the system is switched back to thedebugging mode at the fake breakpoint, the original breakpoint is reset,and the fake breakpoint is deleted. As a result, debugging is performedtwice. Also, implementing data breakpoints in software can greatlyreduce the performance of the Application being debugged, as it is usingadditional resources on the same physical processor.

SUMMARY

In one general aspect, there is provided a debugging apparatus,including: a breakpoint setting unit configured to store a firstinstruction corresponding to a breakpoint in a table and insert abreakpoint instruction into the breakpoint, the breakpoint instructionconfigured to stop a program currently being executed and includingcurrent location information of the first instruction, and aninstruction execution unit configured to selectively execute one of thebreakpoint instruction and the first instruction, according to a valueof a status bit.

In the debugging apparatus, the breakpoint setting unit may be furtherconfigured to: store the first instruction in a first entry of thetable, and store a second instruction, which is to be executed after theexecution of the first instruction, in a second entry of the table.

In the debugging apparatus, the instruction execution unit may befurther configured to: execute the first instruction in the table, andsubsequently return an execution order to the second instruction, afterthe execution of the first instruction, with reference to the secondentry.

In the debugging apparatus, the instruction execution unit may befurther configured to: execute the breakpoint instruction, and inresponse to the execution of the breakpoint instruction, switch thestatus bit to a second state, in response to the status bit being placedin a first state.

In the debugging apparatus, the instruction execution unit may befurther configured to: execute the first instruction, and in response tothe execution of the first instruction, switch the status bit to thefirst state, in response to the status bit being placed in the secondstate.

In the debugging apparatus, the instruction execution unit may include:a program counter configured to store an execution location of theprogram, a bit register configured to store the status bit therein, anda controller configured to: maintain a value of the program counter, orchange the value of the program counter to indicate the firstinstruction in the table, in response to the value of the programcounter reaching an address of the breakpoint.

In the debugging apparatus, the controller may be further configured tochange the status bit after the changing of the value of the programcounter, to indicate the first instruction in the table.

In another general aspect, there is provided a debugging apparatus,including: a breakpoint setting unit configured to store a firstinstruction corresponding to a breakpoint in a table and insert abreakpoint instruction into the breakpoint, the breakpoint instructionconfigured to stop a program currently being executed and includingcurrent location information of the first instruction, a program counterconfigured to store an execution location of the program, a bit registerconfigured to store a status bit therein, and a controller configuredto: maintain the program counter to allow the breakpoint instruction tobe executed and subsequently switch the status bit to a second state, inresponse to the execution of the breakpoint instruction, in response tothe status bit being placed in a first state, in response to the programcounter pointing to the breakpoint, and change the program counter topoint to the location of the first instruction to allow the firstinstruction to be executed and subsequently switch the status bit to thefirst state, in response to the execution of the first instruction, inresponse to the status bit being placed in the second state, in responseto the program counter pointing to the breakpoint.

In the debugging apparatus, the breakpoint setting unit may be furtherconfigured to store the first instruction and a second instructiontogether in the table, the second instruction to be executed after theexecution of the first instruction.

In the debugging apparatus, the controller may be further configured tochange the value of the program counter to indicate the secondinstruction, after the execution of the first instruction.

In another general aspect, there is provided a debugging method,including: storing a first instruction corresponding to a breakpoint ina table and inserting a breakpoint instruction into the breakpoint, thebreakpoint instruction stopping a program currently being executed andincluding current location information of the first instruction, inresponse to a status bit being placed in a first state, in response to aprogram counter pointing to the breakpoint: switching the status bit toa second state, maintaining the program counter, and executing thebreakpoint instruction, and in response to the status bit being placedin the second state, in response to the program counter pointing to thebreakpoint: switching the status bit to the first state, changing theprogram counter to point to the location of the first instruction, andexecuting the first instruction.

In the debugging method, inserting the breakpoint instruction mayinclude storing the first instruction and a second instruction togetherin the table, second instruction to be executed after the execution ofthe first instruction.

In another general aspect, there is provided a debugging method,including: setting a breakpoint in a program, in response to thebreakpoint being encountered during the execution of the program,determining whether a status bit is placed in a first state, in responseto it being determined that the status bit is placed in the first state:switching the status bit to a second state, executing the breakpointinstruction, and performing debugging of the program.

The debugging method may further include: in response to the debuggingof the program being complete: resuming the program, and determiningwhether the status bit is placed in the first state.

The debugging method may further include: in response to it beingdetermined that the status bit is not placed in the first state:switching the status bit to the first state, executing the firstinstruction, and executing the second instruction.

In another general aspect, there is provided a debugging apparatus,including: a breakpoint setting unit configured to set a breakpoint in aprogram, an instruction execution unit configured to: in response to thebreakpoint being encountered during the execution of the program,determine whether a status bit is placed in a first state, and inresponse to it being determined that the status bit is placed in thefirst state: switch the status bit to a second state, execute thebreakpoint instruction, and perform debugging of the program.

In the debugging apparatus, in response to the debugging of the programbeing complete, the instruction execution unit may be further configuredto: resume the program, and determine whether the status bit is placedin the first state.

In the debugging apparatus, in response to it being determined that thestatus bit is not placed in the first state, the instruction executionunit may be further configured to: switch the status bit to the firststate, execute the first instruction, and execute the secondinstruction.

A non-transitory computer-readable information storage medium storing aprogram for implementing the methods.

Other features and aspects may be apparent from the following detaileddescription, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a debugging apparatus.

FIG. 2 is a diagram illustrating an example of a breakpoint instruction.

FIG. 3 is a diagram illustrating an example of a memory unit.

FIG. 4 is a diagram illustrating an example of an instruction executionunit.

FIGS. 5A through 5E are diagrams illustrating an example of theoperation of a debugging operation.

FIG. 6 is a flowchart illustrating an example of a debugging method.

Throughout the drawings and the detailed description, unless otherwisedescribed, the same drawing reference numerals will be understood torefer to the same elements, features, and structures. The relative sizeand depiction of these elements may be exaggerated for clarity,illustration, and convenience.

DETAILED DESCRIPTION

The following detailed description is provided to assist the reader ingaining a comprehensive understanding of the methods, apparatuses,and/or systems described herein. Accordingly, various changes,modifications, and equivalents of the systems, apparatuses and/ormethods described herein will be suggested to those of ordinary skill inthe art. The progression of processing steps and/or operations describedis an example; however, the sequence of steps and/or operations is notlimited to that set forth herein and may be changed as is known in theart, with the exception of steps and/or operations necessarily occurringin a certain order. Also, descriptions of well-known functions andconstructions may be omitted for increased clarity and conciseness.

FIG. 1 illustrates an example of a debugging apparatus.

Referring to FIG. 1, a debugging apparatus 100 may set a breakpoint in aparticular part of a program to be debugged, and may debug the programat the breakpoint. For example, the debugging apparatus 100 may stop theprogram at the breakpoint, may acquire a system access right, and mayexamine the state of the execution of the program or the state of asystem. The debugging apparatus 100 may include a breakpoint settingunit 101, an instruction execution unit 102, and a memory unit 103.

The memory unit 103 may be divided into a first memory area 104 and asecond memory area 105. The program and a breakpoint instruction 107 forstopping the program may be stored in the first memory area 104. Aninstruction 108 originally in the place of the breakpoint instruction107 and a jump instruction 109 (i.e., jump D) for jumping to aninstruction (i.e., instruction D), to be executed after the execution ofthe instruction 108, may be stored in the second memory area 105.

The breakpoint setting unit 101 may set a breakpoint 106 in the program.

The breakpoint setting unit 101 may move an instruction at thebreakpoint 106, e.g., the instruction 108, from the first memory area104 to the second memory area 105, and may insert the breakpointinstruction 107 into the breakpoint 106. The breakpoint instruction 107may stop the execution of the program. Current location information ofthe instruction 108, for example, the address of the instruction 108 inthe second memory area 105, may be included in a particular field of thebreakpoint instruction 107.

The breakpoint setting unit 101 may store the instruction 108 in a firstentry of the second memory area 105, and may store an address of theinstruction to be executed after the execution of the instruction 108,i.e., instruction D, in a second entry of the second memory area 105below the instruction 108. The breakpoint setting unit 101 may alsostore the jump instruction 109, which may be an instruction to jump fromthe instruction 108 to instruction D in response to the program beingresumed.

In response to the breakpoint 106 being encountered during the executionof the program, the instruction execution unit 102 may selectivelyexecute one of the breakpoint instruction 107 and the instruction 108according to the value of a status bit.

The status bit may be stored in a bit register. The status bit may beplaced in a first or second state or may have a value of 0 or 1. Thestatus bit may be initially set to a default value of, for example, 0.The value of the status bit may automatically change after the executionof one of the breakpoint instruction 107 and the instruction 108 by theinstruction execution unit 102.

For example, in response to the status bit having a value of 0, theinstruction execution unit 102 may execute the breakpoint instruction107. As a result, the program may be stopped, and the state of theprogram or the system may be examined in a debugging mode. Then, thestatus bit may be set to 1. For example, the instruction execution unit102 may set the status bit to 1 during the debugging mode.

On the other hand, in response to the status bit having a value of 1,the instruction execution unit 102 may execute the instruction 108. Forexample, in response to the debugging of the program being complete andthus the system being released from the debugging mode, the instructionexecution unit 102 may execute the instruction 108 without executing thebreakpoint instruction 107.

That is, the debugging apparatus 100 may insert the address of theinstruction 108 in the second memory area 105 into the breakpointinstruction 107, and thus may allow a program counter to indicate theinstruction 108 in the second memory area 105 in response to the systembeing released from the debugging mode. As a result, it may be possibleto smoothly switch back to the normal mode by executing the instruction108 originally at the breakpoint 106 and currently in the second memoryarea 105.

FIG. 2 illustrates an example of a breakpoint instruction.

Referring to FIGS. 1 and 2, the breakpoint instruction 107 may beinserted into the breakpoint 106 in the first memory area 104 of thememory unit 103 by the breakpoint setting unit 101. In response to thebreakpoint instruction 107 being executed during the execution of aprogram, the program may be stopped, and the debugging of the programmay be performed. The breakpoint instruction 107 may include an addressfield 201. The address field 201 may store the address of theinstruction 108 originally in the place of the breakpoint instruction107. For example, in response to the breakpoint 106 being set in theplace of instruction C and thus instruction C being moved from the firstmemory area 104 to the second memory area 105, the address ofinstruction C in the second memory area 105 may be stored in the addressfield 201. The instruction execution unit 102 may selectively executeone of the breakpoint instruction 107 and the instruction 108. Forexample, the instruction execution unit 102 may reference the addressfield 201 of the breakpoint instruction 108 to execute the instruction107.

FIG. 3 illustrates an example of a memory unit.

Referring to FIG. 3, the memory unit 103 may include an instructionstorage unit 301 and a table storage unit 302. The instruction storageunit 301 may store a plurality of instructions that constitute aprogram. A breakpoint may be set in the program simply by replacing oneof the instructions, for example, an instruction 304, with a breakpointinstruction 303. The instruction 304 may be moved from the instructionstorage unit 301 to the table storage unit 302, and may be stored in anentry of a table. In an entry next to the entry in which the instruction304 is stored, a jump instruction 305 for jumping to an instruction(e.g., instruction D), to be executed after the execution of theinstruction 304, may be stored.

Referring to FIG. 3, the instruction storage unit 301 and the tablestorage unit 302 may share the same physical space. Alternatively, thetable storage unit 302 may account for part of the instruction storageunit 301, which may be used as an instruction memory. In one example,any instruction in the table storage unit 302 may be easily executed,simply by adjusting a program counter without the need to move thecorresponding instruction from the table storage unit 302 to theinstruction storage unit 301.

FIG. 4 illustrates an example of an instruction execution unit.

Referring to FIGS. 3 and 4, the instruction execution unit 102 mayinclude a program counter 401, a status register 402, a controller 403,and an executioner 404.

The program counter 401 may store an execution location of a program.For example, the execution location of the program may be the address ofthe next instruction to be executed. The executioner 404 may execute aninstruction at the address indicated by the program counter 401. Thevalue of the program counter 401 may be changed by the controller 403.

The bit register 402 may store a status bit. The status bit may have avalue of 0 or 1. The bit register 402 may be initially set to one of thevalues of 0 and 1 as a default value, and the value of the bit register402 may be changed from the default value by the controller 403.

In response to the value of the program counter 401 reaching the addressof a breakpoint, the controller 403 may determine whether the value ofthe status register 402 has a value of 0 or 1. In response to the valueof the status register 402 having a value of 0, the controller 403 maymaintain the value of the program counter 401, may control theexecutioner 404 to execute an instruction at the address indicated bythe program counter 401, i.e., the breakpoint instruction 303 in theinstruction storage unit 301, and may set the status register 402 to 1.

On the other hand, in response to the value of the status register 402having a value of 1, the controller 403 may set the program counter 401to an address included in the breakpoint instruction 303, may controlthe executioner 404 to execute an instruction at the address included inthe breakpoint instruction 303, i.e., the instruction 304 in the tablestorage unit 302, and may set the status register 402 to 0. Therefore,the executioner 404 may execute any instructions indicated by theprogram counter 401, including those included in the table storage unit302.

FIGS. 5A through 5E illustrate an example of the operation of adebugging apparatus.

Referring to FIG. 5A, assume that a first memory area 501 is filled witha plurality of instructions (e.g., A, B, and C), that a second memoryarea 502 is empty, and that a breakpoint corresponds to instruction B.

Referring to FIG. 5B, in response to the breakpoint being set in aprogram, a breakpoint instruction BR may be inserted into the place ofinstruction B in the first memory area 501, and instruction B may bemoved to the second memory area 502. Breakpoint instruction BR hascurrent location information of instruction B. Jump instruction “jump C”for jumping to instruction C after the execution of instruction B may bestored in the second memory area 502 below instruction B.

Referring to FIG. 5C, in response to the breakpoint being encounteredduring the is execution of the program, one of breakpoint instruction BRand instruction C may be selectively executed, according to the value ofa status bit. For example, in response to the status bit having adefault value of 0, the value of a program counter may be maintained,and thus, breakpoint instruction BR may be executed. As soon as theexecution of breakpoint instruction BR begins, the status value may beset to 1. In response to breakpoint instruction BR being executed, theprogram may be stopped, and may then be debugged in a debugging mode. Asthe value of the program counter may not change until the system isswitched back to a normal mode from the debugging mode, the value of theprogram counter may still indicate breakpoint instruction BR.

Referring to FIG. 5D, in response to the status bit having a value of 1,the value of the program counter may be changed, based on the addressincluded in breakpoint instruction BR to indicate instruction B in thesecond memory area 502. Then, the status bit may be set back to 0. As aresult, instruction B in the second memory area 502 may be executed assoon as the system is switched back to the normal mode.

Referring to FIG. 5E, after the execution of instruction B in the secondmemory area 502, the value of the program counter may be changed toindicate instruction C due to jump instruction jump C, and thus, theexecution of instruction C may begin.

FIG. 6 illustrates an example of a debugging method.

Referring to FIGS. 1, 4, and 6, in operation 601, a breakpoint may beset in a program. For example, the breakpoint setting unit 101 may storethe first instruction 108 at the breakpoint 106 in the table 105, andmay insert the breakpoint instruction 107, which may stop the programand may include current location information of the first instruction108, into the original location of the first instruction 108.Thereafter, the breakpoint setting unit 101 may store the firstinstruction 108 in a first entry of the table 105, and may store asecond instruction to be executed after the execution of the firstinstruction 108 in a second entry of the table 105.

Thereafter, in operation 602, in response to the breakpoint beingencountered during the execution of the program, it may be determinedwhether a status bit is placed in a first state. For example, thecontroller 403 of the instruction execution unit 102 may determinewhether the bit register 402 is set to a default value of 0.

In response to it being determined in operation 602 that the status bitis placed in the first state, in operation 603, the status bit may beswitched to a second state; in operation 604, the breakpoint instruction107 may be executed; and in operation 605, the debugging of the programmay be performed. For example, the controller 403 of the instructionexecution unit 102 may change the value of the bit register 402 from 0to 1, may maintain the value of the program counter 401, and may controlthe executioner 404 to execute the breakpoint instruction 107.

In response to the debugging of the program being complete, in operation606, the program may be resumed, and the method may return to operation602.

On the other hand, in response to it being determined in operation 602that the status bit is not placed in the first state, in operation 607,the status bit may be switched to the first state; in operation 608, thefirst instruction 108 may be executed; and in operation 609, the secondinstruction may be executed. For example, the controller 403 of theinstruction execution unit 102 may change the value of the bit register402 from 1 to 0, may change the value of the program counter 401 toindicate the first instruction 108 in the table 105 with reference tothe address included in the breakpoint instruction 107, and may controlthe executioner 404 to execute the first instruction 108.

As described above, even if an instruction at a breakpoint is moved fromits original location to another location, it may be possible to readilyexecute the instruction without the need to move the instruction back toits original location. Therefore, it may be possible to reduceunnecessary memory read/write operations and quickly switch from adebugging mode to a normal mode.

The processes, functions, methods and/or software described herein maybe recorded, stored, or fixed in one or more computer-readable storagemedia that includes program instructions to be implemented by a computerto cause a processor to execute or perform the program instructions. Themedia may also include, alone or in combination with the programinstructions, data files, data structures, and the like. The media andprogram instructions may be those specially designed and constructed, orthey may be of the kind well-known and available to those having skillin the computer software arts. Examples of computer-readable mediainclude magnetic media, such as hard disks, floppy disks, and magnetictape; optical media such as CD-ROM disks and DVDs; magneto-opticalmedia, such as optical disks; and hardware devices that are speciallyconfigured to store and perform program instructions, such as read-onlymemory (ROM), random access memory (RAM), flash memory, and the like.Examples of program instructions include machine code, such as producedby a compiler, and files containing higher level code that may beexecuted by the computer using an interpreter. The described hardwaredevices may be configured to act as one or more software modules thatare recorded, stored, or fixed in one or more computer-readable storagemedia, in order to perform the operations and methods described above,or vice versa. In addition, a computer-readable storage medium may bedistributed among computer systems connected through a network andcomputer-readable codes or program instructions may be stored andexecuted in a decentralized manner.

As a non-exhaustive illustration only, the devices described herein maybe incorporated in or used in conjunction with mobile devices such as acellular phone, a personal digital assistant (PDA), a digital camera, aportable game console, and an MP3 player, a portable/personal multimediaplayer (PMP), a handheld e-book, a portable tablet and/or laptopcomputer (e.g. personal computer (PC)), a global positioning system(GPS) navigation, and devices such as a desktop computer (e.g. PC), ahigh definition television (HDTV), an optical disc player, a setupand/or set top box, and the like, consistent with that disclosed herein.

A computing system or a computer may include a microprocessor that iselectrically connected with a bus, a user interface, and a memorycontroller. It may further include a flash memory device. The flashmemory device may store N-bit data via the memory controller. The N-bitdata is processed or will be processed by the microprocessor and N maybe 1 or an integer greater than 1. Where the computing system orcomputer is a mobile apparatus, a battery may be additionally providedto supply operation voltage of the computing system or computer.

It will be apparent to those of ordinary skill in the art that thecomputing system or computer may further include an application chipset,a camera image processor (CIS), a mobile Dynamic Random Access Memory(DRAM), and the like. The memory controller and the flash memory devicemay constitute a solid state drive/disk (SSD) that uses a non-volatilememory to store data.

A number of examples have been described above. Nevertheless, it shouldbe understood that various modifications may be made. As an example, theexample values of “0” and “1” may be interchanged or replaced, asappropriate. For example, suitable results may be achieved if thedescribed techniques are performed in a different order and/or ifcomponents in a described system, architecture, device, or circuit arecombined in a different manner and/or replaced or supplemented by othercomponents or their equivalents. Accordingly, other implementations arewithin the scope of the following claims.

What is claimed is:
 1. A debugging apparatus, comprising: a breakpointsetter configured to store a first instruction at a breakpoint in atable and insert a breakpoint instruction at the breakpoint, thebreakpoint instruction configured to stop a program currently beingexecuted and comprising current location information of the firstinstruction; and an instruction executor configured to, in response tothe breakpoint being encountered during the execution of the program,execute the first instruction in response to a value of a status bitbeing a first state, and execute the breakpoint instruction in responseto the value of the status bit being a second state, wherein the firstinstruction is distinct from the breakpoint instruction.
 2. Thedebugging apparatus of claim 1, wherein the breakpoint setter is furtherconfigured to: store the first instruction in a first entry of thetable; and store a second instruction, which is to be executed after theexecution of the first instruction, in a second entry of the table. 3.The debugging apparatus of claim 2, wherein the instruction executor isfurther configured to: execute the first instruction in the table; andsubsequently return an execution order to the second instruction, afterthe execution of the first instruction, with reference to the secondentry.
 4. The debugging apparatus of claim 1, wherein the instructionexecutor is further configured to: in response to the execution of thebreakpoint instruction, switch the status bit to the first state.
 5. Thedebugging apparatus of claim 4, wherein the instruction executor isfurther configured to: in response to the execution of the firstinstruction, switch the status bit to the second state, in response tothe status bit being placed in the first state.
 6. The debuggingapparatus of claim 1, wherein the instruction executor comprises: aprogram counter configured to store an execution location of theprogram; a bit register configured to store the status bit therein; anda controller configured to: maintain a value of the program counter; orchange the value of the program counter to indicate the firstinstruction in the table, in response to the value of the programcounter reaching an address of the breakpoint.
 7. The debuggingapparatus of claim 6, wherein the controller is further configured tochange the status bit after the changing of the value of the programcounter, to indicate the first instruction in the table.
 8. A debuggingapparatus, comprising: a breakpoint setter configured to store a firstinstruction at a breakpoint in a table, and insert a breakpointinstruction at the breakpoint, the breakpoint instruction configured tostop a program currently being executed and comprising current locationinformation of the first instruction; a program counter configured tostore an execution location of the program; a bit register configured tostore a status bit; and a controller configured to maintain the programcounter to allow the breakpoint instruction to be executed and switchthe status bit to a second state, in response to the program counterpointing to the breakpoint and the status bit being a first state, andchange the program counter to point to the location of the firstinstruction to allow the first instruction to be executed and switch thestatus bit to the first state, in response to the program counterpointing to the breakpoint and the status bit being the second state,wherein the first instruction is distinct from the breakpointinstruction.
 9. The debugging apparatus of claim 8, wherein thebreakpoint setter is further configured to store the first instructionand a second instruction together in the table, the second instructionto be executed after the execution of the first instruction.
 10. Thedebugging apparatus of claim 9, wherein the controller is furtherconfigured to change the value of the program counter to indicate thesecond instruction, after the execution of the first instruction.
 11. Adebugging method, comprising: storing a first instruction at abreakpoint in a table and inserting a breakpoint instruction into thebreakpoint, the breakpoint instruction stopping a program currentlybeing executed and comprising current location information of the firstinstruction; in response to a status bit being placed in a first state,and a program counter pointing to the breakpoint: switching the statusbit to a second state; maintaining the program counter; and executingthe breakpoint instruction; and in response to the status bit beingplaced in the second state and the program counter pointing to thebreakpoint: switching the status bit to the first state; changing theprogram counter to point to the location of the first instruction; andexecuting the first instruction, wherein the first instruction isdistinct from the breakpoint instruction.
 12. The debugging method ofclaim 11, wherein inserting the breakpoint instruction comprises storingthe first instruction and a second instruction together in the table,second instruction to be executed after the execution of the firstinstruction.
 13. A non-transitory computer-readable information storagemedium storing a program for implementing the method of claim
 11. 14. Adebugging method, comprising: setting a breakpoint in a program; inresponse to the breakpoint being encountered during the execution of theprogram, determining whether a status bit is placed in a first state; inresponse to it being determined that the status bit is placed in thefirst state: switching the status bit to a second state; executing thebreakpoint instruction; and performing debugging of the program, whereinthe breakpoint instruction is distinct from a first instruction storedat the breakpoint.
 15. The debugging method of claim 14, furthercomprising, in response to the debugging of the program being complete:resuming the program; and determining whether the status bit is placedin the first state.
 16. The debugging method of claim 14, furthercomprising, in response to it being determined that the status bit isnot placed in the first state: switching the status bit to the firststate; executing the first instruction; and executing the secondinstruction.
 17. A non-transitory computer-readable information storagemedium storing a program for implementing the method of claim
 14. 18. Adebugging apparatus, comprising: a breakpoint setter configured to set abreakpoint in a program; an instruction executor configured to: inresponse to the breakpoint being encountered during the execution of theprogram, determine whether a status bit is placed in a first state; andin response to it being determined that the status bit is placed in thefirst state: switch the status bit to a second state; execute thebreakpoint instruction; and perform debugging of the program, whereinthe breakpoint instruction is distinct from a first instruction storedat the breakpoint.
 19. The debugging apparatus of claim 18, wherein, inresponse to the debugging of the program being complete, the instructionexecutor is further configured to: resume the program; and determinewhether the status bit is placed in the first state.
 20. The debuggingapparatus of claim 18, wherein in response to it being determined thatthe status bit is not placed in the first state, the instructionexecutor is further configured to: switch the status bit to the firststate; execute the first instruction; and execute the secondinstruction.